OK, some ideas that on face value aren't too bad. I applaud anyone who can think outside the box and see a new and reasonable idea.
I'm a little confused Lodown when you say that "...most of ERSA, ERSA amendments and NOTAM relate to IFR multi-engine operations.". Can you point out which sections of these are exclusively the domain of ME IFR ops? Perhaps runway data? The availability of lighting? Maybe, ATC and CTAF freq's? I have no problem if AsA decide to carve off the back section on pre-flight planning in to a seperate book that gets issued seperately. In fact, snarek makes a good point. They could publish a 'Level 1' document for all ops and another 'Level 2' one for IFR specific stuff - that way, Joe Lighty could just get the Level 1 document.
I'm not going to assume, however, that it is a simple matter of "Hey, lets publish another document". Someone has to sit there, edit and proof-read the thing. How will that affect the cost? Dunno...
Loose leaf documents are a pain in the a@$e to amend and the most time consuming (DAP & Jepp users know this) - that's why people like the whole document to be reissued. It saves valuable time.
snarek, with respect, the fact that AOPA has asked all its members to participate in the survey is one of the very reasons I began this post. I would like to see AsA get a BALANCED opinion from the industry - which requires all drivers to respond (even you Lodown!).